Portable data terminals (PDTs) are a type of data collection devices used to collect, interpret, process, and ultimately transfer data to a larger data processing system. PDTs generally integrate a mobile computer, an alpha-numeric or numeric keypad, and at least one data acquisition device. The mobile computer portion is generally similar to known touch screen consumer oriented portable computing devices (e.g. “Pocket PCs” or “PDAs”), such as those available from PALM, HEWLETT PACKARD, and DELL. The data acquisition device generally comprises a device that captures data from an encoded source, for example, radio frequency IDs (RFID), images, and bar codes. Data may also be captured via keypad entry and utilization of a touch pad associated with the mobile computer. In addition to the integration of a data acquisition device and keypads, PDTs distinguish from consumer oriented portable computing devices through the integration of more durable or “industrial” versions of their constituent components. Additionally, PDTs tend to provide improved power performance by utilizing superior batteries and power management circuits. PDTs are available from several sources. including the assignee of the present application: HAND HELD PRODUCTS. INC.
FIG. 1 is a plan view of a known PDT 100. The PDT 100 utilizes an elongated water resistant body 102 supporting a variety of components, including: a battery (not illustrated); a touch screen 106 (generally comprising a LCD screen under a touch sensitive panel); a keypad 108 (including a scan button 108a); a scan engine 110 (not illustrated); and a data/charging port 112 (also not illustrated). The scan engine 110 may comprise, for example, an image engine, a laser engine or and RFID engine. The data/charging port 112 typically comprises a proprietary mechanical interface with one set of pins or pads for the transmitting and receiving data (typically via a serial interface standard such as USB or RS-232) and a second set of pins or pads for receiving power for operating the system and/or charging the battery.
In use, the user may actuate the scan key 108a to initiate data capture via the scan engine 110. The captured data is analyzed, e.g. decoded, to identify the information represented. The decoded data is stored and possibly displayed on the PDT 100. Additional processing of the data may take place on the PDT 100 and/or a data processing resource to which the data is transmitted via any available transport mechanism on the PDT 100. Some examples of known transport mechanisms utilized by PDT's include: Bluetooth, WiFi, GSM, CDMA, USB, IrDA, removable FLASH memory, parallel, and serial (including for example, RS-232).
FIG. 2 is a block diagram of a known PDT 200. A central processing unit (CPU) 202 receives data from and outputs data to other sub-systems for storage, transmission and additional processing. The CPU 202 typically comprises one or more of a number of off the shelf solutions including: embedded processors, such as an XSCALE processor available from INTEL; general purpose processors, such as a PENTIUM 4 available from INTEL; or any number of custom solutions including pre-configured field programmable gate arrays (FPGAs) and application specific integrated circuits (ASICs). Overall operation of the CPU 202 is controlled by software or firmware (typically referred to as an operating system) stored in one or more memory locations 205n, including RAM 205a and FLASH memory 205b. Examples of suitable operating systems for the PDT 200 include graphical user interfaces such as WINDOWS MOBILE, WINDOWS CE, WINDOWS XP, LINUX, PALM, and OSX.
In general, communication to and from the CPU 202 and among the various sub-components takes place via one or more ports or busses, including a main system bus 204; a plurality of Universal Asynchronous Receiver/Transmitter (UART) ports 206n; and a Dual Universal Asynchronous Receiver/Transmitter (DUART) 210.
A variety of secondary processors may be provided to perform general and application specific functions. The example illustrated in FIG. 2 provides three such processors: a field programmable gate array (FPGA) 212; an auxiliary processor 214; and an LCD controller 216. The FPGA 212 may comprise any number of FPGAs including the Virtex-4 family of FPGAs available from XILINX. The FPGA 212 is used to interface with certain data acquisition system as described hereinafter. The auxiliary processor 214 may comprise any number of embedded (or general purpose) processors, including the PICmicro® family of microcontrollers available from MICROCHIP TECHNOLOGY. The auxiliary processor 214 interfaces with and controls a variety of data input devices including, for example a touch sensitive panel 222, a keypad 224, and a scan key or trigger 226. The LCD controller 216 may comprise any number of available controllers including for example, one of the available EPSON LCD controllers. As its name and connections suggest, the LCD controller 216 controls the display of images on an LCD display 220, such as any number of displays available from SHARP. The combination of the LCD 220 and the touch sensitive panel 222 is often referred to as a “touch screen.”
The PDT 200 may further include a plurality of communication links such as an 802.11 communication link 240, an IR communication link 242, a Bluetooth communication link 244, and a cellular communication link 246 for communication with a cellular network such as a network in accordance with the Global System for Mobile Communications (GSM). The 802.11 communication link 240 interfaces with the CPU 202 via the main system bus. The IR communication link 242, and Bluetooth communication link 244 are connected to the CPU 202 via UART channels 206n. The cellular communication link 246 is connected to the CPU 202 via the DUART 210. Wired communication may be conducted via a UART, such as the UART 206e. Each of the communication links facilitates communication with a remote device and is principally used to transfer and receive data.
In use, the PDT 200 may be configured to activate a data acquisition system based on the actuation of a key on the keypad 224 (including the Trigger 226) or a touch on the touch panel 222. A variety of suitable data collection systems are available for integration into the PDT 200. In the example shown in FIG. 2, two such systems are illustrated: an image signal generation system 250 and an RFID reader unit 260. One or more of the data acquisition systems may be administered by the FPGA 212. In the illustrated case, the FPGA 212 initiates operation of the image generation system 250 and accumulates data received there from prior to depositing such data in memory 205n. Possible configurations of the FPGA 212 are illustrated in U.S. Pat. No. 6,947,612 incorporated herein by reference. Communication with, and control of, the RFID reader unit 260 is via the system bus 208.
The image signal generating system 250 generally comprises a two dimensional solid state image sensor 252, available in such technologies as CCD, CMOS, and CID, for capturing an image containing data, e.g. an, image, a bar code or a signature. Two-dimensional solid state image sensors generally have a plurality of photo sensor picture elements (“pixels”) which are formed in a pattern including a plurality of rows and a plurality of columns of pixels. The image signal generating system 250 further includes an imaging optics (not shown) focusing an image onto an active surface of the image sensor 252. Image sensor 252 may be incorporated on an image sensor IC chip having disposed thereon image sensor control circuitry, image signal conditioning circuitry, and an analog-to-digital converter. FPGA 212 manages the capture and transfer of image data into memory 205n. Decoding may be performed by the CPU 202 or any suitable secondary processor. Examples of suitable image signal generation system 250 include an IMAGETEAM 5x00VGA/5x00MPX imaging module of the type available from Hand Held Products, assignee of the present application.
One use of the image signal generating system 250 is reading and interpreting bar codes such as bar code 275 on an item 270. In this mode, when trigger button 226 is actuated, the CPU 202 cause the appropriate control signals to be sent to the image sensor 252. In response thereto, the image sensor 252 outputs digital image data including a representation of the bar code symbol 275. This data is acquired by the FPGA 212 where it is collected and subsequently transferred to memory 205n. In accordance with a decoding program (not specifically illustrated) an attempt may be made to decode the bar code represented in the captured digital image representation. The capture and decoding of image data may occur automatically in response to a trigger signal being generated, usually by activation of the trigger 226 or a pre-selected key on keypad 224. For example, the CPU 202 may be configured, typically through execution of a program resident in memory 205n, to continuously capture and decode bar code symbols represented therein until either a successful decode is completed or the trigger 226 is released. The cycle may also be terminated by timing out after a number of unsuccessful decode attempts.
In addition to having a decode mode of operation, the image signal generation system 250 may also be configured for an image capture mode of operation. In an image capture mode of operation, an electronic image representation is captured without attempting a decode. The captured electronic image representation may be one or more of (i) stored into a designated memory location of memory 205n, (ii) transmitted to an external device, or (iii) displayed on LCD 220. This mode may be used to capture, for example an image of a signature or damage to a package.
The RFID reader unit 260 includes an RF oscillation and receiver circuit 262 and a data decoder 264. RFID reader unit 260 may be configured to read RF encoded data from a passive RFID tag, such as tag 277, which may be disposed on article 270. In such a case, RF oscillation and receiver circuit 262 transmits a carrier signal to the passive tag which in turn converts the carrier energy to voltage form and actuates a transponder (not shown) to transmit a radio signal representing the encoded tag data. RF oscillator and receiver circuit 262, in turn, receives the radio signal from the tag and converts the data into a digital format. Data decoder 264, typically including a low cost microcontroller IC chip, decodes the received radio signal information received by RF oscillator and receiver circuit 262 to decode the encoded identification data originally encoded into RFID tag 277.
RFID reader unit 260 may, for example, operate in a selective activation mode or in a continuous read operating mode. In a selective activation mode, RFID reader unit 260 broadcasts radio signals in an attempt to activate a tag or tags in its vicinity in response to an RFID trigger signal being received. In a continuous read mode, the RF oscillation and receiver circuit 262 continuously broadcasts radio signals in an attempt to actuate a tag or tags in proximity with unit automatically, without receiving a trigger signal. PDT 200 may be configured so that the CPU 202 recognizes a trigger signal under numerous conditions, such as: (1) actuation of the trigger 226; (2) receipt of an RFID trigger instruction (for example generated by a software program); or (3) a determination that some other predetermined condition has been satisfied.
There has been interest in integrating global positioning satellite (GPS) systems with portable devices such as PDTs. In a GPS system, a GPS receiver receives a signal from one or more GPS satellites, calculates a location of the receiver from the received signal(s). To calculate a location, the GPS receiver demodulates the signal(s) from the GPS satellite and acquires orbit data for the GPS satellite. Then, from an orbit of the GPS satellite, current time information, and a delay time of a received signal, the GPS receiver derives a three-dimensional location by solving a series of simultaneous equations.
A consumer GPS receiver receives a signal an L1 band from the GPS satellite, namely, a spectrum diffusion signal electric wave referred to as a C/A (Coarse/Acquisition) code and carries out a positioning calculation. In the consumer space, PDAs with integrated GPS systems have been marketed by GARMIN and NAVMAN. The benefits imparted by the combination of a PDA and a GPS revolve around reducing the number of devices a user carries; providing a superior display for use with GPS navigation software; and the ability to integrate location data with data produced by software running on the PDA.
In a PDT, such as PDTs 100 and 200, battery life is a significant differentiator between competing products. Current GPS systems draw an inordinate amount of current and are not typically optimized for power consumption. The present inventors have recognized a need for methods and apparatus to incorporate current GPS systems into PDTs while maintaining the extended battery life that separates PDTs from consumer oriented portable computing devices.